Hornady 6mm ARC.

Frank Green

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www.bartleinbarrels.com
Yup. BRA in 28” will likely have no prob with 2950 or barely under.
Brady’s gun at work is a 24” barrel. With his hand loads he is getting 2889fps average with a 105gr bullet. Not bad for a gas gun and a 24” barrel.

Numbers where from a Labradar just a couple of weeks ago.

Later, Frank
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BadAccountant

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Many people use our mag kits to run grendel and 224 valk... so I would suspect the 6ARC could be made to work as well. Just gotta get those feed lips tuned for the smaller cases is all.

Obviously the focus of the cartridge is semi-auto. I get that... but I also know people, and there will be a ton of them running this in bolt guns.
A light-weight antelope and mountain rifle chambered in 6 ARC would be the tits. A friend has a mini action he rechambered for 6 Turbo and it rocks.
 

6brshooter

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You better go with dasher if you want that speed and not be in the high node. That's right about where I'm running my 6 Dasher with H4350 and 105 hybrids. 6BRA can certainly get there, but it will be grunting... and most certainly in the high node.
Yep, 2950 is gonna be max on a bra unless its got a musket length barrel.
 

CarbonMTN

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The problem that I have at this moment is Twist rates. From manufactures, I'm seeing 1- 7.25, 1- 7.5, and 1- 8. This is sounding a lot like its going to be another twist sensitive bullet like what plagues the 224 Valkyrie.
 

BadAccountant

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The problem that I have at this moment is Twist rates. From manufactures, I'm seeing 1- 7.25, 1- 7.5, and 1- 8. This is sounding a lot like its going to be another twist sensitive bullet like what plagues the 224 Valkyrie.
I don't see why.

There's enough data and collective experience from shooters and bullet manufacturers on what makes a 6mm tick. Just about every top PRS competitor is shooting a 6mm at this point, and the bullets designs are nothing new. We're taking the same 6mm bullets we've shot for years and sticking them into the same case that wildcatters have been shooting it out of for years. 6 LBC/Grendel/Turbo have been around for a long time, and we have a pretty good idea of which twists work and which do not.

The 6 ARC is so close to those designs and their performance level that I don't anticipate problems relating to twist rates at all, even if someone decides to shoot heavies like a DTAC.
 

spife7980

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The problem that I have at this moment is Twist rates. From manufactures, I'm seeing 1- 7.25, 1- 7.5, and 1- 8. This is sounding a lot like its going to be another twist sensitive bullet like what plagues the 224 Valkyrie.
Those should all stabilize the 108 eld Ive seen the data on.
 
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bjay

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When hornady's article released and comparing this 6arc to 308..i swear i though it was a 308 boltface 6mm for ar15 spec!!!
Just when I about to reach napkins tp wipe drool...i realized its grendel face!!!
I sold my accurate 6mmar here
We already got 3 diff 6mm from 6mmar.com there's 243 lbc 6 fatrat 6 grendel just to name a few...so whats new about this cartridge???
 

BadAccountant

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When hornady's article released and comparing this 6arc to 308..i swear i though it was a 308 boltface 6mm for ar15 spec!!!
Just when I about to reach napkins tp wipe drool...i realized its grendel face!!!
I sold my accurate 6mmar here
We already got 3 diff 6mm from 6mmar.com there's 243 lbc 6 fatrat 6 grendel just to name a few...so whats new about this cartridge???
Slightly different shoulder (probably so you can't chamber 6.5 grendel in it and blow up the gun) and aside from that, not much. It's a 6 grendel for all intents and purposes with factory support and a SAAMI submission. That's it as far as I can tell.
 
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bjay

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Slightly different shoulder (probably so you can't chamber 6.5 grendel in it and blow up the gun) and aside from that, not much. It's a 6 grendel for all intents and purposes with factory support and a SAAMI submission. That's it as far as I can tell.
At least they didnt name it 6 grendel..or some will make the other way around disaster...where 6.5 grendel shooters grabbing 6 grendel ammos from shelves
 

lennyo3034

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When hornady's article released and comparing this 6arc to 308..i swear i though it was a 308 boltface 6mm for ar15 spec!!!
Just when I about to reach napkins tp wipe drool...i realized its grendel face!!!
I sold my accurate 6mmar here
We already got 3 diff 6mm from 6mmar.com there's 243 lbc 6 fatrat 6 grendel just to name a few...so whats new about this cartridge???
Biggest thing is Hornady factory support.
 
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Ledzep

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I'm pretty sure the statements at 18:30 and 19:10, combined with the context of 18:30 to 19:35 were meant more in the realm of it's the best jack-of-all-trades that fits in an AR-15... not that literally every aspect of the 6 ARC is better than every aspect of every other AR-15 cartridge. Check 10:00-10:30. 19:15-19:25.
 
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steve123

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IMO the sweet spot for bullet weight in these 6mm Grendel based cartridges is 95 gr bullets. Going about 50 -100 faster compared to the 105-ish weights, you get a little less drop, pretty much the same wind drift, and less recoil, which to me makes shooting these cartridges all that more pleasant to use, especially with a brake.

I was surprised how well these did at 1000Y one day in heavy winds. That's what I love about AR's, fast follow up shots so you can pound steel FAST until the wind changes. That day my friend with his 6.5PRC was having trouble staying on the steel because of wind fluctuations. Basically I was shooting 3-4 shots to his 1 so I learned quickly where mine would hit in the lulls or gusts.
 

Ridenemwild

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I honestly belive the whole so a grendel wont chamber thing is BS. There are plenty of cartridges that can accidentally be chambered in the wrong barrel. The only reason to move the shoulder back is to fit the 108 eldm at mag length and not have it sit too deep in the case. I have been researching doing a 6mm variant for an AR15 of mine and most of the research says the 95gr bullets seem to be the best performers. The little cases just dont hold enough powder to shoot the 100+ grain bullets as effectively. And now on this they limit the case capacity even more just to fit a certain bullet. I think this could be a miss for hornady. I would much rather shoot a 95gr SMK at 2900fps than their eld at 2700ish.
 

bodhisafa

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If I am reading this correctly, the 6 arc is still a more versatile cartridge than 6.5 Grendel ?
 

Ridenemwild

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If I am reading this correctly, the 6 arc is still a more versatile cartridge than 6.5 Grendel ?

I would say yes. With the ability to shoot from 55gr to 100+gr bullets it should be an extremely versatile cartridge for any animal less than about 200lbs and targets out to 1000 yrds
 

BadAccountant

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I honestly belive the whole so a grendel wont chamber thing is BS. There are plenty of cartridges that can accidentally be chambered in the wrong barrel. The only reason to move the shoulder back is to fit the 108 eldm at mag length and not have it sit too deep in the case. I have been researching doing a 6mm variant for an AR15 of mine and most of the research says the 95gr bullets seem to be the best performers. The little cases just dont hold enough powder to shoot the 100+ grain bullets as effectively. And now on this they limit the case capacity even more just to fit a certain bullet. I think this could be a miss for hornady. I would much rather shoot a 95gr SMK at 2900fps than their eld at 2700ish.
Well, you still can get that extra velocity, but likely won't be doing it from an AR15. A bolt gun will allow you step up those pressure a bit. Out of an AR, I think that the 95s are probably the best overall performer, and the heavier bullets will likely lend themselves towards bolt guns a bit more.
 

mark5pt56

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I wonder if the 6.5G disciples are in a frenzy? Haha:ROFLMAO:

Has anyone heard rumblings about LMT making barrels for the MRP?
 

Ledzep

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Anyone seen any load data from the powder/bullet companies?
Do you want 52ksi AR data or 60ksi bolt gun data?

ETA: 52ksi max loads. Please work your way up to and do not exceed these in an AR-15. Some of this correlates similarly to 6mm AR data, but I would drop at least .5-1.5gr from any listed 'max' 6mm AR load you find. Obviously you should drop 10% and work up with anything.

8208xbr: 25.3gr
H4895: 25.5gr
LeverEvolution: 29.7gr (Best velocity)
AA2520: 28gr
RL-15: 27.8gr

It's important to understand that you WILL NOT SEE PRESSURE SIGNS between 52ksi and 60ksi but you WILL PUT EXTRA STRESS ON AR-15 BOLT LUGS by going over 52-55ksi. Not an immediate Kaboom, but fatigue failure on the lugs is much more likely to eventually catch up with you. Also note the above is with Hornady brass. If you're forming from 6.5G, especially Lapua, I'd drop charges even more.
 
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MakeSawdust

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Those twists will stabilize 115s DTACs and VLDs.
I've run 115 DTAC in 3 243AI barrels ( about 7500 of them). 2 8 twists and a 7.5 twist. I shoot in the Midwest at an avg of 1000 above sea level. In the 8 twist barrels the gun would hammer and the bc was as stated or better when it was 80+ degrees. Below that the gun would open up slightly and the bc would fall off until it was below 55 degrees or so. Then everything went to hell. This was shooting them at 2950-3050 fps.

With a 7.5 twist accuracy is better overall and the bc stays pretty consistent until it gets in the 20s or 30s. At those temps I have to adjust the bc down to get things to line up.

I think a 7 twist or something between a 7.5 and a 7 is the sweet spot for the DTAC to get the most out of them, especially with cartridges close to the BR case and variants.

If you never plan to shoot in cold weather or at low altitude you can get by with less, but it won't work for everyone.
 

BadAccountant

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I've run 115 DTAC in 3 243AI barrels ( about 7500 of them). 2 8 twists and a 7.5 twist. I shoot in the Midwest at an avg of 1000 above sea level. In the 8 twist barrels the gun would hammer and the bc was as stated or better when it was 80+ degrees. Below that the gun would open up slightly and the bc would fall off until it was below 55 degrees or so. Then everything went to hell. This was shooting them at 2950-3050 fps.

With a 7.5 twist accuracy is better overall and the bc stays pretty consistent until it gets in the 20s or 30s. At those temps I have to adjust the bc down to get things to line up.

I think a 7 twist or something between a 7.5 and a 7 is the sweet spot for the DTAC to get the most out of them, especially with cartridges close to the BR case and variants.

If you never plan to shoot in cold weather or at low altitude you can get by with less, but it won't work for everyone.
Most of the barrels I've seen from Preferred and other companies are a straight 7 twist. I don't think HDY wants to make the same mistake that Federal et al. did when rolling out the 224V. They want to make sure they don't have the keyholing issues with those heavies like people had with the 88s and 90s in the 224V.
 

sam4886

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There's 15 years of 6mm Grendel load data. This isn't a ground up endeavor for anyone.
I'm aware of that. I have and load for a 6mm predator using XBR and benchmark, but having more data, especially manufacturer tested stuff, is always nice. Its nice to have options when you can't find your favorite powder...
 

rockchalk06

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I pre-ordered a 20" Faxon 1:8 barrel for this last week. Don't know much about it other than a few videos, but I'm intrigued. I have a lower I've been meaning build something around for over a year.
 

Ledzep

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I did a 6 ARC barrel for my Mausingfield. 28" Proof Competition contour, 1:7.5". Had to buy a .223 Bolt face and open it up in the lathe and mill. Filed the extractor to fit. Running MDT BR magazines (no modifications necessary). Feeding has some small bugs to work out, but I'm pretty sure I know what will fix it.

With LeverEvolution running 105-110gr bullets at 2870-2960fps. Definitely warm, but not "spicy". :) Rifle is 23lb as pictured. Feels like a damn 22 magnum for recoil.

ARCm56ARC.jpg
Arcm56ARCbf.jpg
 

MakeSawdust

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Some of us are interested in having 6 bra/dasher performance with the option of running factory ammo when work is busy, and there isn't time to reload. For that purpose, the idea of running 6ARC in a bolt gun is appealing. Obviously, if time were never an issue, we would just run the BR family and reload.

Outside of the competition realm, I don't see a big draw for it.
 
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tsu45

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If any Hornady reps reading this I’ve got a hot tip for you: if you want this round to take off, you are in the prime market conditions to shift production towards it and drive adoption.
 

wes1

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So, I have a Tikka T3 chambered in 6mmAR(6 Grendel). Looks like I can shoot the factory 6ARC ammo and "fireform" to my 6AR chamber? (moving the shoulder forward) or am I missing something?
 

BadAccountant

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So, I have a Tikka T3 chambered in 6mmAR(6 Grendel). Looks like I can shoot the factory 6ARC ammo and "fireform" to my 6AR chamber? (moving the shoulder forward) or am I missing something?
You might* be able to. They pushed the shoulder back 30 thou if I'm not mistaken, so it shoulder chamber. I would not fire full power loads to fireform until you know more about the way the cartridge is supported by the chamber.

But pistol powder + COW should work.
 

Ledzep

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So, I have a Tikka T3 chambered in 6mmAR(6 Grendel). Looks like I can shoot the factory 6ARC ammo and "fireform" to my 6AR chamber? (moving the shoulder forward) or am I missing something?
You need to do something to ensure the case head is pushed against the bolt face or you will have problems with primers backing out, variable head space on fired cases, and potentially case head separations.

While loose head space doesn't usually get me too scared, .029" is quite a lot.

@reubenski I don't think anyone is saying factory ammo is comparable to BR/Dasher. Two separate ideas-- Factory ammo is available when you don't want to reload (for practice, etc..), and when you hand load you can get pretty impressive results out of a bolt gun. My 28" barrel is getting 2950fps with 105gr class bullets and LeverEvolution with a little bit of room to go faster. Edit to add: Factory ammo is going 2820-2850 in the same barrel (108's). Obviously a longer barrel is necessary to get there.

The only downer I see in the bolt-gun world is the availability of Grendel/PPC bolts and bolt heads. Hopefully more action makers will hop on board. @karagias
 
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reubenski

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You need to do something to ensure the case head is pushed against the bolt face or you will have problems with primers backing out, variable head space on fired cases, and potentially case head separations.

While loose head space doesn't usually get me too scared, .029" is quite a lot.

@reubenski I don't think anyone is saying factory ammo is comparable to BR/Dasher. Two separate ideas-- Factory ammo is available when you don't want to reload (for practice, etc..), and when you hand load you can get pretty impressive results out of a bolt gun. My 28" barrel is getting 2950fps with 105gr class bullets and LeverEvolution with a little bit of room to go faster. Edit to add: Factory ammo is going 2820-2850 in the same barrel (108's). Obviously a longer barrel is necessary to get there.

The only downer I see in the bolt-gun world is the availability of Grendel/PPC bolts and bolt heads. Hopefully more action makers will hop on board. @karagias
Just like the 224 Valk initial barrel life and MV reports are optimistic and on the high end. Having had a .22 Grendel and 6 AR, I don't see a way you're going to equal a 6 BR load....unless you stomp on the ARC and sandbag the BR in a low accuracy node...which isn't an accurate comparison. And like my 22 Grendel, CFE gets me better velocity but 8208 gets me better accuracy and temp stability. You're not going to get all three and still compare velocities to a like-hottrodded BR going 2950